A Transcode and Prefetch Technique of Multimedia Presentations for Mobile Terminals

Abstract

As mobile communication technologies are developing rapidly, this paper proposes a technique of playing multimedia presentation on mobile terminals in a more stable environment. To play multimedia presentation on mobile terminals in a stable way, there are problems. Since mobile terminals use low bandwidth, it is impossible to play multimedia presentation which has large amount of data. Even after prefetching, limited memory of mobile terminals prohibit stable play of the presentation. On this basis, the paper proposes a prefetching technique combined with transcoding method to solve these problems. For this aim, a multimedia presentation should be transcoded to be playable in mobile terminals. It is not that every stream existing in the presentation is transcoded, but that only the selected according to the stream selection policy, i.e. scheduling, are transcoded. This is to save transcoding time. By this way, the early delay time, which includes transcoding time in mobile terminals, can be minimized. Moreover, after undergoing transcode, the presentation is to be prefetched in compliance with the memory size of the mobile terminal. This process makes it possible for the presentation to be played in a more stable way. Through the experiments of 90 presentations, it becomes possible to select superior selection policy after applying prefetch and transcode. The presentation, which adopts more superior policy, shows more stable play as well as reduced early delay time.